POST 177. July 11, 2021. CORONAVIRUS. the Delta variant is “the 2020 version of Covid-19 on steroids,”… “It is the most hypertransmissible, contagious version of the virus we’ve seen to date…it’s a superspreader strain if there ever was one .” but… now, there’s a Delta Plus variant…

“The highly contagious Delta variant is now the dominant version of the coronavirus in the United States, according to figures released this week by the Centers for Disease Control and Prevention.

Delta now accounts for more than half of infections across the country, a benchmark health experts had predicted it would pass. Delta is believed to be about 60 percent more transmissible than Alpha, a variant first detected in Britain that became dominant in the United States this spring. Alpha now accounts for just 28.7 percent of cases, the C.D.C. reports.”

“Delta accounts for nearly all virus cases in southwestern Missouri, where a hospital recently ran out of ventilators.” (P)

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“Viruses mutate all the time, including the SARS-CoV-2 coronavirus that’s caused the Covid-19 pandemic. Although most genetic changes are innocuous, some can make the mutant more adept at infecting cells, for example, or evading antibodies. Such “fitter” variants can outcompete other strains, so that they become the predominant source of infections. A succession of more-transmissible variants has emerged over the past year, each harboring a constellation of mutations. The most worrisome so far is the so-called delta variant. It has spread to more than 100 countries since it was first reported in India in October, leading to surges in cases and hospitalizations, especially in places where less than half the adult population has been fully immunized. It’s the dominant strain now in many countries, including in the U.K. and the U.S.” (A)

“Twenty-four states have seen an uptick of at least 10% in Covid-19 cases over the past week, Johns Hopkins University data shows, as health experts and the federal government keep pressing for more people to get vaccinated.

The rapid spread of the Delta variant of the coronavirus has only ratcheted up the pressure.

That variant, first identified in India, accounted for 51.7% of all new Covid-19 infections in the country over the two weeks that ended Saturday, the US Centers for Disease Control and Prevention has estimated.

“We should think about the Delta variant as the 2020 version of Covid-19 on steroids,” Andy Slavitt, a former senior adviser to Joe Biden’s Covid Response Team, told CNN on Wednesday. “It’s twice as infectious. Fortunately, unlike 2020, we actually have a tool that stops the Delta variant in its tracks: It’s called vaccine.”” (B)

“Fifteen months after the novel coronavirus shut down much of the world, the pandemic is still raging. Few experts guessed that by this point, the world would have not one vaccine but many, with 3 billion doses already delivered. At the same time, the coronavirus has evolved into super-transmissible variants that spread more easily. The clash between these variables will define the coming months and seasons. Here, then, are three simple principles to understand how they interact. Each has caveats and nuances, but together, they can serve as a guide to our near-term future.

1. The vaccines are still beating the variants.

The vaccines have always had to contend with variants: The Alpha variant (also known as B.1.1.7) was already spreading around the world when the first COVID-19 vaccination campaigns began. And in real-world tests, they have consistently lived up to their extraordinary promise…

2. The variants are pummeling unvaccinated people.

Vaccinated people are safer than ever despite the variants. But unvaccinated people are in more danger than ever because of the variants. Even though they’ll gain some protection from the immunity of others, they also tend to cluster socially and geographically, seeding outbreaks even within highly vaccinated communities…

3. The longer Principle No. 2 continues, the less likely No. 1 will hold.

Whenever a virus infects a new host, it makes copies of itself, with small genetic differences—mutations—that distinguish the new viruses from their parents. As an epidemic widens, so does the range of mutations, and viruses that carry advantageous ones that allow them to, for example, spread more easily or slip past the immune system to outcompete their standard predecessors. That’s how we got super-transmissible variants like Alpha and Delta. And it’s how we might eventually face variants that can truly infect even vaccinated people…” (C)

“Here are five things you need to know about the Delta variant.

1. Delta is more contagious than the other virus strains.

Delta is the name for the B.1.617.2. variant, a SARS-CoV-2 mutation that originally surfaced in India. The first Delta case was identified in December 2020, and the strain spread rapidly, soon becoming the dominant strain of the virus in both India and then Great Britain. Toward the end of June, Delta had already made up more than 20% of cases in the U.S., according to Centers for Disease Control and Prevention (CDC) estimates. That number is rising swiftly, prompting predictions that the strain will soon become the dominant variant here…

2. Unvaccinated people are at risk.

People who have not been fully vaccinated against COVID-19 are most at risk.

In the U.S., there is a disproportionate number of unvaccinated people in Southern and Appalachian states including Alabama, Arkansas, Georgia, Mississippi, Missouri, and West Virginia, where vaccination rates are low (in some of these states, the number of cases is on the rise even as some other states are lifting restrictions because their cases are going down)…

3. Delta could lead to ‘hyperlocal outbreaks.’

If Delta continues to move fast enough to accelerate the pandemic, Dr. Wilson says the biggest questions will be about transmissibility—how many people will get the Delta variant and how fast will it spread?

The answers could depend, in part, on where you live—and how many people in your location are vaccinated, he says. “I call it ‘patchwork vaccination,’ where you have these pockets that are highly vaccinated that are adjacent to places that have 20 percent vaccination,” Dr. Wilson says. “The problem is that this allows the virus to hop, skip, and jump from one poorly vaccinated area to another.”

4. There is still more to learn about Delta.

One important question is whether the Delta strain will make you sicker than the original virus. “Based on hospitalizations tracked in Great Britain [which has been about a month ahead of the U.S. with Delta], the variant is probably a bit more pathogenetic,” Dr. Wilson says. While more research is needed, early information about the severity of Delta includes a study from Scotland that showed the Delta variant was about twice as likely as Alpha to result in hospitalization in unvaccinated individuals (and vaccines reduced that risk significantly)…

5. Vaccination is the best protection against Delta…

“Like everything in life, this is an ongoing risk assessment,” says Dr. Yildirim. “If it is sunny and you’ll be outdoors, you put on sunscreen. If you are in a crowded gathering, potentially with unvaccinated people, you put your mask on and keep social distancing. If you are unvaccinated and eligible for the vaccine, the best thing you can do is to get vaccinated.”” (D)

“What’s different about delta

Since it was first identified in October 2020, the delta variant has distinguished itself as the most transmissible known variant of the coronavirus. Without widespread vaccination and rigid adherence to public health measures, such as masking and social distancing, SARS-CoV-2 has been allowed to mutate and evolve over time and will continue to do so.

Data suggest this variant is three times as infectious as the original coronavirus strain, according to Dr. Tom Frieden, former CDC director who founded Resolve to Save Lives. But it remains unclear if this virus is deadlier or leads to more severe illness, said Dr. Yvonne Maldonado, chief of the Division of Pediatric Infectious Diseases at Stanford University School of Medicine. Some data suggest that symptoms associated with a delta variant infection — a runny nose and sore throat — may be slightly different than earlier in the pandemic. For example, the loss of one’s sense of smell is being reported less frequently.

The variant devastated India this spring, smashing global records for daily rates of new infection and threatening to collapse parts of that nation’s health care system. Since then, the World Health Organization has said this variant is on track to dominate all known infections. And, Frieden added, it has moved the goal posts for target vaccination rates.

“The threshold for herd immunity is higher with delta than it was before,” Frieden said…

What’s next?

For the coming weeks and months ahead, Frieden warned of a dynamic we’re already seeing: “a tale of two countries — vaccinated and unvaccinated.” COVID-19 infections will remain low, with occasional upticks, in highly vaccinated places. But in communities where most people remain unvaccinated, Frieden said, “you’re already seeing much higher rates — five, 10, 20 times higher.” He noted that’s lower “compared to the deadly spring,” but that cases are increasing rapidly.

“What the delta variant does is it shortens the fuse between the beginning of spread and explosive spread,” Frieden said.

“This variant is like tinder sitting in a dry forest” waiting for a spark among the unvaccinated, said Dr. F. Perry Wilson, an epidemiologist who directs the Clinical and Translational Research Accelerator at the Yale School of Medicine.

In this phase of the pandemic, the concept of herd immunity has become hyperlocal, he added. Even if the national numbers are looking good, it obscures how vulnerable some counties remain to devastating outbreaks. For people who are vaccinated but live in areas where most of their neighbors are not, Wilson recommended wearing a face mask when indoors with others.

That can be particularly problematic in rural parts of the country, where the health care system was already stretched thin even before the rise of COVID-19. In parts of Missouri or Arkansas, where roughly a third of people are vaccinated, Wilson said the increased transmissibility of the delta variant, and others that may mutate and ascend to take its place, could further overwhelm rural hospitals.

Wilson said he doubts any state has the ability to continue micromanaging outbreaks at that level.

“The best choice you can make for yourself is vaccination,” he said. (E)

“After months of data collection, scientists agree: The delta variant is the most contagious version of the coronavirus worldwide. It spreads about 225% faster than the original version of the virus, and it’s currently dominating the outbreak in the United States.

A new study, published online Wednesday, sheds light on why. It finds that the variant grows more rapidly inside people’s respiratory tracts and to much higher levels, researchers at the Guangdong Provincial Center for Disease Control and Prevention reported.

On average, people infected with the delta variant had about 1,000 times more copies of the virus in their respiratory tracts than those infected with the original strain of the coronavirus, the study reported.

In addition, after someone catches the delta variant, the person likely becomes infectious sooner. On average, it took about four days for the delta variant to reach detectable levels inside a person, compared with six days for the original coronavirus variant…

Their findings suggest that people who have contracted the delta variant are likely spreading the virus earlier in the course of their infection.

And the scientists underscore the importance of quarantining immediately for 14 days after coming into contact with someone diagnosed with COVID-19, as the U.S. Centers for Disease Control and Prevention recommends.”” (F)

“It is the most hypertransmissible, contagious version of the virus we’ve seen to date, for sure—it’s a superspreader strain if there ever was one,” says Eric Topol, a professor of molecular medicine and an executive vice president at the Scripps Research Institution. The U.S. is poorly prepared, he says. Less than half of the nation’s population is fully vaccinated—and that number is much lower in some states, particularly in the South and Mountain West. “We’ve been warned three times by the U.K.,” Topol says, referring to previous surges in early 2020 and last winter. “This time is the third warning.”” (G)

“Several of the vaccines in use still appear to work well against Delta.

A Public Health England study published in May found that the variant only slightly reduced the effectiveness of two doses of the Pfizer and AstraZeneca vaccines. The Moderna vaccine is expected to perform similarly well.

A preprint from Public Health England found that two doses of either vaccine also provided exceptional protection against hospitalization from the Delta variant.

But: The Delta variant does seem to pose a greater risk to people who have received only one dose.

According to Public Health England, a single dose of either AstraZeneca’s or Pfizer’s vaccine reduced a person’s risk of developing Covid-19 symptoms by 33 percent, compared with 50 percent for the Alpha variant.

A single dose of AstraZeneca showed reduced protection against hospitalization. (There was no major difference with Pfizer.)

Preliminary evidence also suggests that the two Chinese vaccines, Sinovac and Sinopharm, may be less effective against Delta. Those vaccines are being used in more than 90 countries, including the Seychelles, Chile, Bahrain and Mongolia, which have all outpaced the U.S. vaccination rate. All four ranked among the top 10 countries with the worst Covid outbreaks as recently as last week. “If the vaccines are sufficiently good, we should not see this pattern,” said Jin Dongyan, a virologist at the University of Hong Kong.” (H)

“But the question of whether the vaccines remain as effective at preventing infection, and therefore transmission and spread, is more fraught.

Early figures from the real-world studies in the UK in May found that two doses of the Pfizer vaccine were 88 per cent effective at preventing symptomatic infection with the Delta variant. A month later, that number was revised down to 79 per cent by Scottish researchers.

Canadian scientists on Saturday, using a combination of methods, estimated that the Pfizer jab was 87 per cent effective at preventing infection with the Delta variant. That was “comparable”, the researchers said, to the 89 per cent protection the shot provided against the Alpha variant, first identified in Britain.

A fourth study, compiled by Israel’s health ministry, details of which were reported this week, suggested the Pfizer vaccine was much less effective against symptomatic infection with Delta, providing only 64 per cent protection. Pfizer and Israeli health officials, however, were quick to caution that the study was based on preliminary and highly localised infection numbers, and had other methodological weaknesses.

The varied assessments reflect the difficulty of conducting real-world assessments of vaccine efficacy. During trials, scientists can select participants, monitor who receives a vaccine and who receives a placebo, and then see who gets infected and who does not, providing a trove of data. Once a vaccination campaign gets under way, scientists lose that control, and other factors may affect who gets sick, making it more difficult to reach firm conclusions.

“Observational vaccine study data are not randomised trial data,” Natalie Dean, an assistant professor of biostatistics at Emory University in Atlanta, Georgia, wrote on Twitter. The Israeli findings should not “negate” other studies that showed higher vaccine efficacy, she said, as the small size of the epidemic in Israel was one of several “fudge factors” that could impact results…

Peter English, a public health expert who previously advised PHE, cautioned that while the data on efficacy against hospitalisation was generally positive, the vaccines’ ability to prevent the transmission of Delta was far less clear.

“Delta is so much more infectious, it’s better at finding people who aren’t sufficiently immune and infecting them,” he said, adding that it would take time for reliable numbers on transmission to accumulate.” (I)

“On Tuesday, Fauci, President Joe Biden’s chief medical adviser, appeared tentative about the (Israeli) findings in an interview with NPR, and said the percentage could be the result of the country testing more people for COVID.

This could make it appear as if the vaccine is less effective.

He said: “We don’t have enough data or enough numbers to know what that means.

“It could mean that they just are testing a heck of a lot more people who are asymptomatically infected, and they’re seeing a larger percentage of people infected. Hence a diminution in the efficacy of the vaccine.”

Fauci told NPR the apparent decline in effectiveness was “something we would certainly want to pay attention to, but I’m not so sure we can make any major conclusions based on the information we have right now.”” (O)

““Pfizer announced on Thursday that its COVID vaccine booster shot could further protect individuals from “all currently known variants” of COVID-19 — including the highly transmittable Delta variant. The booster shot is currently undergoing trials, the company said, and has shown “encouraging clinical trial data in a small number of participants in our study.”

Pfizer said that the initial two doses that patients received have elicited “strong immune responses” against the Delta variant and that current studies are focused on whether the booster shot will increase that response even further.

Trial data has shown that when given six months after the second dose, Pfizer’s booster has a “consistent tolerability profile” and neutralizes an immune response. Pfizer and BioNTech plan to share their booster data with the Food and Drug Administration in August and file for emergency use authorization shortly thereafter, a Pfizer spokesperson said.

While Pfizer believes the booster will be highly effective against COVID variants, the company said it is also developing an updated Pfizer-BioNtech COVID vaccine that will target the Delta variant specifically. mRNA for a new vaccine trial is already being manufactured, the company said, and clinical studies are expected to begin in August, pending approval.” (J)

“The data have not been published, nor peer-reviewed. The vaccine makers said they expected to submit their findings to the Food and Drug Administration in the coming weeks, a step toward gaining authorization for booster shots.

But the companies’ assertions contradict other research, and several experts pushed back against the claim that boosters will be needed.

“There’s really no indication for a third booster or a third dose of an mRNA vaccine, given the variants that we have circulating at this time,” said Dr. Céline Gounder, an infectious disease specialist at Bellevue Hospital Center in New York. “In fact, many of us question whether you will ever need boosters.”

Federal agencies also sounded a dubious note on Thursday night. Generally, Americans who have been fully vaccinated do not need a booster shot at this time, the F.D.A. and the Centers for Disease Control and Prevention said in a joint statement…

Citing data from Israel, Pfizer and BioNTech suggested their vaccine’s efficacy “in preventing both infection and symptomatic disease has declined six months post-vaccination.” Noting the rise of Delta and other variants, the companies said that “a third dose may be needed within 6 to 12 months after full vaccination.”

Health officials in Israel have estimated that full vaccination with the Pfizer-BioNTech offers only 64 percent efficacy against the Delta variant. (Efficacy against the original virus is greater than 90 percent.)

But Israel’s estimates have been contradicted by a number of other studies finding that the vaccine is highly effective at preventing infection — against all variants. One recent study showed, for example, that the mRNA vaccines like Pfizer’s trigger a persistent immune reaction in the body that may protect against the coronavirus for years.

“Pfizer looks opportunistic by hanging an announcement on the back of very early and undigested data from Israel,” said John Moore, a virologist at Weill Cornell Medicine in New York. “When the time is right for using boosters here, the decision isn’t theirs to make.”” (K)

“The coronavirus vaccine created by Johnson & Johnson is effective against the new, highly transmissible Delta variant of the virus, according to two infectious disease experts at the University of Alabama at Birmingham. But a booster might not be out of the question, despite what the federal government is saying.

“Great news on the J&J vaccine,” Dr. Jeanne Marrazzo, the director of the division of infectious diseases at UAB, said in a press conference on Thursday. She cited two recent studies, one confirming that the vaccine creates strong immunity for COVID-19 in general, and that the immunity lasts for at least eight months. The other shows it’s effective against Delta, too.

“The message is the J&J vaccine is inducing really good, really long term immunity, at least right now,” she said. “It appears to be about 90% effective against the Delta variant, very similar to the mRNA vaccines, which is really, I think, really exciting and good news.”

Because of the vaccine’s effectiveness, she said it’s unlikely people who got the J&J vaccine will need to get a second “booster” shot any time soon…

Marrazzo said she doesn’t think people who got the J&J shot will need a second dose of that particular shot, but said some so-called “mix and match” studies have shown that early data suggest mixing a J&J shot with one of the mRNA vaccines – either Pfizer or Moderna in the U.S. – could “boost your immune response to COVID dramatically.”

“Theoretically, and at least in the clinical cases, it looks like a good idea,” she said of getting a second, different kind of vaccine as a booster. But she urged that there is not nearly enough real world data to prove that yet, or to recommend it to everyone.

“It almost certainly can’t hurt,” she said. “There’s no downside to it, as far as we know, other than the inconvenience, the side effects, and of course the cost, if you’re paying for it. And there could be a potential benefit.”

But she said she’s not comfortable making that public policy at this point, for a number of reasons. One is the federal guidance. At the time of her press conference, the CDC and FDA had yet to release any guidance on booster shots, and Marrazzo said she was hoping they would release guidance soon. Now, they’re saying not to get a booster…

“I worry that Alabama is going to have the next variant that’s going to be completely vaccine resistant,” Goepfert said. Conditions here are perfect for such an outcome, he said. A low vaccination rate means viruses can spread, but there are enough people who are vaccinated that the virus will inevitably reach a vaccinated person and have the opportunity to mutate to get around those defenses.

Marrazzo and Goepfert both said that future boosters, or new versions of the vaccines, may be needed if such variants develop. And that’s all the more reason for more people to get vaccinated now, according to Goepfert.

“These are the best vaccines we’ve ever made for an adult vaccine,” he said. “They are highly effective, highly effective in older adults, which is very unusual for a vaccine like this… I urge everyone, get information, talk to someone you trust, a healthcare provider, and get vaccinated.”” (L)

“This is an example of evolution in action. At the start of the pandemic, the virus fooled experts by demonstrating an unexpected way to spread: Contagiousness before symptoms, plus an unusually high number of people with completely symptom-free but contagious infections. Aggressive testing and cautious congregation along with masking — the first package of advice — helped curb this.

But this approach likely introduced an evolutionary pressure that favored the emergence of the B.1.1.7 or Alpha variant, a swifter-to-spread version that got to the mask and social distancing corner-cutters. This first set of variants in turn were tamed by the introduction of effective vaccines.

Now the vaccines may be applying further pressure on the virus by winnowing the susceptible population, favoring even more contagious strains that are more able to pick off the harder-to-find susceptible person in the crowd.

The Delta variant will likely fizzle out one way or another as it eventually runs out of easy targets. But, by the rules of evolution, it will promote and then be replaced by the next variant as we march through the Greek alphabet. Perhaps these variants will cause milder symptoms, or perhaps a more severe disease before reaching their limit. As long as susceptible people remain, the virus will continue to do its aimless business of switching it up and hopping from here to there.

Indeed, this pattern will repeat whether or not CDC guidance about masks or distancing or returning to work is updated. This guidance is built to be useful for most people, most of the time, but it will never perfectly protect everyone. Frequent updates can sharpen the focus but, even then, public health guidance remains a blunt instrument usually only followed enthusiastically by those who are already on board with taking safety precautions.

Given these limitations, the only way to truly control the pandemic is to vaccinate more and more people. Just as polio and smallpox and measles and countless other infections continued to cause wide sweeps of harm until a vaccine for each virus was available, so too will this coronavirus shadow us until we are just about all immune — by vaccine or natural disease.”  (M)

“Now, there’s a Delta Plus variant, and governments are understandably concerned.

The Delta Plus variant – also known as B.1.617.2.1 or AY.1 – contains a new mutation in the spike protein the virus uses to enter human cells, called K417N. As it’s still closely linked to Delta, it’s been called Delta Plus rather than another letter in the Greek alphabet, according to WHO’s naming system for COVID-19 variants. So far, Delta Plus has been found in relatively low numbers.

India has already been ravaged by the Delta variant, and COVID-19 cases reached a horrifying peak of 400,000 daily cases in May. Last week, India’s Ministry of Health released a statement on Delta Plus citing three characteristics for concern.

These are: increased transmissibility, stronger binding to receptors of lung cells (suggesting easier entry into human cells), and a potential reduction in response to monoclonal antibodies (which could imply that people’s immune systems may be less effective against this variant, or that they may be less responsive to lifesaving monoclonal antibody treatments).

The Delta Plus variant was found during routine screening of viral RNA sequences uploaded to GISAID, a data sharing platform set up originally to share flu viral sequences – indicating how critical ongoing surveillance is.

Indian epidemiologist Dr Lalit Kant told the BBC that “We need to further scale up our sequencing efforts to identify dangerous variants early and apply containment measures”.

Several scientists have warned that this is not the time for India – or any other country for that matter – to let down its guard.” (N)

PREQUEL

POST 170. June 17, 2021. CORONAVIRUS. “Dr. Ashish Jha…is worried about the potential impact  the delta variant could have in the United States… “I’m concerned about the Delta variant,”… “Why? Most contagious variant yet. Wreaked havoc in India. Spiking cases in UK. Growing rapidly in the US.”

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